In general, an automatic transmission control system for a vehicle is arranged to shift the speed of a transmission up or down to optimum one of preset speed stages sequentially on a step-by-step basis in accordance with the load condition of the vehicle (such as, for example, the vehicle speed or engine rotational speed).
In prior art automatic transmission control systems of the type referred to, however, when a transmission lever is set at a shift position D (drive position) with speed stages ranging from a forward 2 speed position to a forward 7 speed position (F2 to F7) and it is desired to start a vehicle, the vehicle must be started always from the position F2 and be shifted up in speed on a step-by-step basis in a sequential order of F2, F3, F4, . . . and up to the optimum speed stage, which disadvantageously results in that the system requires the large number of shift times, with poor start/acceleration characteristics and considerable speed shift shock.
In view of the above circumstances, it is an object of the present invention to provide a starting speed stage selector which is used in an automatic transmission control system to allow a vehicle to start always from an optimum speed stage in response to load conditions of the vehicle.